Electropolishing process means for an inner surface of a long tube

ABSTRACT

The present invention is an electropolishing process means for an inner surface of a long tube, especially applied to a long tube of greater than two meters and a diameter range between 0.3 to 5 cm. Wherein, the present invention comprises at least one tube, one complex electrode; an inner surface of the tube is for electropolishing process, and it is an anode as well; the electrode is a cathode and placed on a center of a partition; an end of electrode connects to a cable, the cable is driven by an axial mechanism to be moved toward the axial mechanism itself; inside tube are full of electrolyte, which is an electrifying medium to connect both anode and cathode, further, electrolyte cooperates with electrode to move for electropolishing process the inner surface of tube.

1. FIELD OF THE INVENTION

[0001] The present invention is an electropolishing process means for aninner surface of a long tube, especially applied to a long tube ofgreater than two meters and an inside diameter range between 0.3 to 5cm.

2. BACKGROUND OF THE INVENTION

[0002] A process of electropolishing is to connect a workpiece to ananode and a metal to a cathode, aforesaid whole structure of workpiececonnecting to anode and metal connecting to cathode is put intoelectrolyte for electrifying direct current, thus defects on workpiecesurface are removed and the surface is then shining and smooth. Featuresof electropolishing are that improving surface cleanness, roughness,passivation, etc. For different fields of semiconductor, chemicalindustry, biochemical engineering, food industry, needed tubes ofaforesaid fields are to deliver fluids of those fields, and innersurfaces of tubes are treated by polish or electrolysis to approach highcleanness and anti-corrosion. Especially, products of IC/LCD/III-Vrequire high standards of cleanness and anti-corrosion, thus, applyingthe present invention to said products is a challenge.

[0003] In prior arts of U.S. Pat. Nos. 4,826,582 and 4,849,084, whichwere figuring out part of the technologies of electropolishing a10-meter heat exchange tube, and an electrode device for positioningworkpiece and sealing electrolyte is a must. The prior arts adopt a3-layer structure of delivering electrolyte of high pressure air, butunfortunately said structure is very complicate and only suitable forthe larger diameter workpieces, not for the tube of inside diameterunder 3 cm.

[0004] In prior art of U.S. Pat. No. 5,958,195, which was the technologyof electropolishing an inner surface of a long and bended tube. However,to electropolish a bended tube, electrode must move alone bended curvefor not happening short circuit. The most important parts are a flexibleelectrode and an insulation device. The insulation-device is to avoidshort circuit and non-concentricity, but this kind of devices blockelectrolyte flowing and makes un-average electric field, etc.

[0005] In prior arts of U.S. Pat. Nos. 4,601,802 and 4,705,611, whichoffer a fixture applied an inside tube, and the fixture stabilizes aplurality of axially rotating tubes simultaneously. An end connector cancirculate tube and exhaust gas from an upper end, and electrolyte can berecycled after overflowing. An electrode length is equal to the tubelength, therefore a huge space and a super power supplier are needed tofit such conditions.

[0006] Based on the aforesaid issues, the present inventor of the patenthas being studied and referred to practical experiences and theory fordesigning and effectively improving the prior arts.

SUMMARY OF THE INVENTION

[0007] The first object is to offer an electropolishing process meansfor an inner surface of a long tube, which improves an electrode designand applies theories of macro and micro polishing to an electrode meansfor improving a manufacturing rate in both smoothing and passivationeffect on the surface of workpiece.

[0008] The second object is to offer an electropolishing process meansfor an inner surface of a long tube, which can treat an inner surface ofa tube greater than 2 meters and an inside diameter range of 0.3 to 5cm; a structure of the means is simple to save an equipment cost.

[0009] The third object is to offer an electropolishing process meansfor an inner surface of a long tube, which avoids short circuit andnon-concentricity problems. An electrode of the present invention isinstalled through a center of a partition, so the electrode has acertain distance with the inner surface in tube because the partitionsupports electrode. Therefore, the short circuit and non-concentricityare solved; further, the average electric field is kept all the timebecause of the partition is round.

[0010] The fourth object is to offer an electropolishing process meansfor an inner surface of a long tube, which electrode can be designed asmulti-section, to do so figures out that needing a huge space to storesuch similar equipment; further, the electrode can be added to differentsections depending on needs to improve electrolyzing and polishingresult.

[0011] The appended drawings will provide further illustration of thepresent invention, together with description; serve to explain theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a scheme of a practical application of the presentinvention.

[0013]FIG. 2 is a first preferred embodiment of the present invention.

[0014]FIG. 3 is a preferred embodiment of an electrode of the presentinvention.

[0015]FIG. 4 is a second preferred embodiment of the present invention.

[0016]FIG. 5 is a third preferred embodiment of the present invention.

[0017]FIG. 6 is a sectional view of a partition of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] For different fields of semiconductor, pharmaceutical industrychemical industry, biochemical engineering, food industry, innersurfaces of needed tubes and fitting of aforesaid fields are treated byelectropolishing process for improving surface cleanness, roughness andpassivation results. The present invention comprises an electrolytedelivering system, which makes electrolyte averagely pass through aninner surface of a long tube; a cable, which guides direct current to aworking area of an inner surface of tube, and electrolyte is anelectrifying media to make a complete electric path. An end of the cablecan be added an insulated electrode means, which slowly moves along withan imagine central axis of tube for a cathode electrode not contactingonto an anode electrode, thus short circuit problem is then evaded. Theelectrode means is complex for approaching a huge and fine polishingresult, such as a Cu—W bar.

[0019] Referring to FIG. 1, which is a scheme of a practical applicationof the present invention. Electrolyte is stored in a tank 10, and aheater 11 is inside the tank 10 for keeping electrolyte temperature.Electrolyte passes through a switch 12 and a pipe 23 to a tube 16,wherein the switch 12 is made of Teflon or other heat-resistant andacid-proof materials. The tube 16 is placed on an inclined platform 17,and thus a higher end of tube 16 connects to the pipe 23 for electrolytepassing from higher end to a lower end. Inclined angles of the inclinedplatform 17 can be adjusted to control electrolyte flowing speeds. Tube16 includes at least one electrode (not shown in FIG. 1), which is hungup by a cable 20, and another end of the cable 20 is rolled up by anaxial mechanism 22; The axial mechanism 22 rolls up cable 20 to move theelectrode upward when electropolishing process reaction being proceededinside tube 16. The present invention adopts that electron exchangingfrom an anode half reaction and a cathode half reaction to generate anelectropolishing process result. Tube 16 is an anode, thus an innersurface of tube 16 is anode, and anode looses electrons; the electrodeis cathode, and cathode receives electrons; FIG. 1 does not show theelectrode, so only cable 20 is shown up to represent above connectionrelationship. Tube 16 is about 2 meters long or more than that, soelectrolyte temperature is lower when electrolyte approaching to alowest end of tube 16, thus plural halogen bulbs 15 are placed aroundtube 16 for heating. Electrolyte is recycled after passing through tube16 to a recycling tank 13, then it is delivered back to tank 10 by apump 14 with heat-resistant and acid-proof. As aforesaid, which is acomplete procedure for electropolishing process. Following is a detaildescription.

[0020] Referring to FIG. 2, which is a first preferred embodiment of thepresent invention. In the embodiment, a partition 18, an electrode 21and a propeller 19 are in a tube 16; the electrode 21 is hung up by acable 20 and driven by an axial mechanism 22 to move toward the axialmechanism 22. Electrolyte is full of inside tube 16, and a diameter ofthe partition 18 is slightly smaller than an inner diameter of tube 16(a diameter range of electropolishing process of the present inventionis between 0.3 to 5 cm), therefore partition 18 floats in tube 16 and isalmost perpendicular to the inner surface of tube 16, so partition 18cannot touch onto the inner surface of tube 16. Finally, cable 20electrifies direct current to electrode 21 and through a medium ofelectrolyte to the inner surface; the electropolishing process reactionis then started. Electrode 21 is placed on a center of partition 18, andit is double electrodes, which is complex for approaching a huge andfine polishing result; besides, electrode 21 can be made by differentmaterials, such as copper, wolfram, stainless steel, etc. On the otherhand, electrode 21 can be single as well (not shown in figure), and thesingle electrode is positioned between partition 18 and the propeller19. The reaction is preceded only between them, so electropolishingprocess goes slowly. Propeller 19 is to quickly exhaust air bulbsgenerated by reaction, because air bulbs affect polished surface. Whenelectrolyte flowing from an end close to axial mechanism 22 to anotherend of tube 16, propeller 19 is also driven by axial mechanism 22 toopposite direction, and it rotates and vortex is generated by aforesaidrelative motion as well. Air bulbs in between partition 18 and thepropeller 19 and another side of partition 18 are exhausted fast.Referring to FIG. 5, which is a third preferred embodiment of thepresent invention. Propeller 19 can be instead of a screw slideway 24,and air bulbs go through the screw slideway 24 to outside; obviously,screw slideway 24 functions as propeller 19. As shown in FIG. 2, pluralslots 25 are designed on an outer edge of partition 18, those slots 25make electrolyte flow close to inner surface more fluently and aboundary layer is then broken to generate an average anode membrane,such flow effectively brings air bulbs out. Referring to FIG. 6, whichis a sectional view of a partition of the present invention. Forfluently introducing electrolyte, partition 18 has many holes 26 asmeshes; further, partition 18 is made of Teflon of insulated materialfor saving total energy and enhancing electropolishing process result.Another function of partition 18 is to avoid contacting of negativeelectrode and positive inner surface, hence short circuit andnon-concentricity are solved; further, the average electric field iskept all the time because partition 18 is round. Partition 18 isvariable for different tube diameters.

[0021] Referring to FIG. 3, which is a preferred embodiment of anelectrode of the present invention. The electrode can be made of pluralmaterials for different levels of polishing. A complex electrodeconsists of a first electrode 211 and a second electrode 212 fortwo-stage electropolishing process reaction, and it is to promote resultshown as in FIG. 1.

[0022] Referring to FIG. 4, which is a second preferred embodiment ofthe present invention. An electrode 21 of the preferred embodimentincludes a third electrode 213, a fourth electrode 214, a fifthelectrode 215 and a sixth electrode 216; this is for multi-stagereaction, and it seems each kind of electropolishing process reactioncan be approached from the embodiment.

[0023] While the present invention has been shown and described withreference to preferred embodiments thereof, and in terms of theillustrative drawings, it should be not considered as limited thereby.Thus, the present invention is infinitely used. However, variouspossible modification, omission, and alterations could be conceived ofby one skilled in the art to the form and the content of any particularembodiment, without departing from the scope and the sprit of thepresent invention.

[0024] The invention is disclosed and is intended to be limited only thescope of the appended claims and its equivalent area.

What is claimed is:
 1. An electropolishing process means for an innersurface of a long tube comprising: at least one tube having an innersurface for being polished, said tube being inclined for electrolyteflowing from a higher place to a lower place when electrolytic andpolish being proceeding, tube being made of material of electricconductivity; at least one partition being placed inside tube, saidpartition dividing at least two spaces in tube for electropolishingprocess, a diameter of partition being slightly smaller than an innerdiameter of tube, partition floating in tube and being almostperpendicular to the inner surface of tube, so partition not touchingonto the inner surface of tube; and at least one electrode being placedon a center of partition, the electrode being in a space divided bypartition, an end of electrode connecting to a cable, the cable beingconnected by an axial mechanism, said axial mechanism driving cable tomove electrode toward axial mechanism itself.
 2. The electropolishingprocess means for an inner surface of a long tube cited in claim 1,wherein the means electrolyzes and polishes a range of 0.3 to 5 cm ofthe tube inner diameter.
 3. The electropolishing process means for aninner surface of a long tube cited in claim 1, wherein the meanselectrolyzes and polishes tube greater than two meters.
 4. Theelectropolishing process means for an inner surface of a long tube citedin claim 1, wherein the inner surface is anode of the reaction.
 5. Theelectropolishing process means for an inner surface of a long tube citedin claim 1, wherein the partition is made of one of the followingmaterials: Teflon, insulated material, etc.
 6. The electropolishingprocess means for an inner surface of a long tube cited in claim 1,wherein plural slots are designed on an outer edge of partition, theslots make electrolyte flow close to inner surface more fluently, aboundary layer is then broken to generate an average anode membrane. 7.The electropolishing process means for an inner surface of a long tubecited in claim 1, wherein plural slots are designed on an outer edge ofpartition, the slots make electrolyte flow close to inner surface morefluently, such flow effectively brings out air bulbs generated byreaction.
 8. The electropolishing process means for an inner surface ofa long tube cited in claim 1, wherein the partition has many holes asmeshes for fluently introducing electrolyte.
 9. The electropolishingprocess means for an inner surface of a long tube cited in claim 1,wherein the partition is variable for different tube diameters.
 10. Theelectropolishing process means for an inner surface of a long tube citedin claim 1, wherein the partition can be a plurality depending on eachneed.
 11. The electropolishing process means for an inner surface of along tube cited in claim 1, wherein the electrode is cathode.
 12. Theelectropolishing process means for an inner surface of a long tube citedin claim 1, wherein different materials depending on needs can organizethe electrode.
 13. The electropolishing process means for an innersurface of a long tube cited in claim 1, wherein an end of the electrodeconnecting to cable has a screw structure for fast remove air bulbs. 14.The electropolishing process means for an inner surface of a long tubecited in claim 1, wherein the screw structure is one of the following:propeller, screw slideway.
 15. The electropolishing process means for aninner surface of a long tube cited in claim 1, wherein the electrode canbe organized by a plurality of following materials: copper, wolfram,stainless steel, etc.
 16. The electropolishing process means for aninner surface of a long tube cited in claim 1, wherein the tube isplaced on an inclined platform.
 17. The electropolishing process meansfor an inner surface of a long tube cited in claim 1, wherein a higherend of the tube connects to a pipe, and the pipe connects to a tank. 18.The electropolishing process means for an inner surface of a long tubecited in claim 1, wherein a recycling tank is placed under a lower endof the tube, electrolyte in the recycling tank is delivered back to tankby a pump.
 19. The electropolishing process means for an inner surfaceof a long tube cited in claim 1, wherein plural light bulbs are placedaround tube for heating.
 20. The electropolishing process means for aninner surface of a long tube cited in claim 1, wherein the electrode isdriven by axial mechanism to move a direction opposite to a direction ofelectrolyte flow.